This is an ignition exciter for the J-2 liquid fuel rocket engine. An ignition exciter is a device that generates a high-energy pulse to an igniter (similar to an automobile coil). The exciter shown here is from early J-2 hardware and dates to 1961. The J-2 engine system was the first to use this type ignition system at Rocketdyne. An engine restart was required on the J-2 while in Earth orbit mode to send the Apollo spacecraft on its way to the Moon. On previous engine systems, pyrotechnic igniters were used as one one-start igniters were required.

The J-2 engine, using liquid hydrogen and liquid oxygen, was the powerplant for the second and third stages of the Saturn V launch vehicle which took astronauts to the Moon in the Apollo program. The Saturn V's second stage had a cluster of five J-2s, while the third stage had a single J-2. This exciter was recovered from Rocketdyne's VTS-1 (Vertical Test Stand-1) area, before the stand was torn down in 1996.

The Rocketdyne Division of Rockwell International donated this artifact to the Museum in 2001.